Double Chocolate Chip Cookies

Directions

1. 1
   In a medium bowl, beat the butter with an electric mixer until fluffy, about 1 minutes. Next, add the brown sugar and beat another minute. Add the egg yolk and vanilla extract and beat until well combined.
2. 2
   In a separate bowl, whisk together the cocoa powder, flour, espresso powder, baking soda and salt until no lumps remain. Add the dry ingredients to the wet ingredients in two increments, mixing between each addition. Finally, stir in the chocolate chunks.
3. 3
   Cover the dough and chill it for at least 1 hour. The dough can be made in advance or even frozen.
4. 4
   When ready to bake, preheat the oven to 350°F and spray a cookie sheet with cooking spray (or line it with parchment paper).
5. 5
   Scoop out 9-10 dough balls and roll them in your hands to form a ball before placing them on the sheet. Leave at least an inch between them. Bake for 8-10 minutes. Check the cookies at 8 minutes. If they smell fragrant and the edges are set, remove them from the oven. Sprinkle with the salt, if using.
6. 6
   Let the cookies cool on the baking sheet for 5 minutes before serving.